Improved insomnia is one pathway underlying the anti‐suicidal properties of clozapine

Abstract

AbstractBackgroundInsomnia is common in schizophrenia and associated with suicide. Clozapine has anti‐suicidal properties and beneficial effects on sleep. Whether effects on insomnia mediate the anti‐suicidal properties of clozapine remains unclear.MethodsIn n = 76 patients from the Clinical Antipsychotic Trials of intervention effectiveness schizophrenia trial using a within‐subjects design, we investigated whether improvement in terminal insomnia was associated with improvement in suicidal ideation (SI) after treatment with non‐clozapine antipsychotics, and then after treatment with clozapine, using binary logistic regression. Terminal insomnia and SI over the past 2 weeks were assessed before and after both non‐clozapine antipsychotic and clozapine treatment with the Calgary Depression Scale for Schizophrenia.ResultsThere was no association between improved terminal insomnia and resolution of SI after treatment with non‐clozapine antipsychotics (OR = 0.2, 95% CI 0.0–9.0, p = 0.41). In the same patients, improved terminal insomnia was associated with resolution of SI after clozapine treatment (OR = 14.6, 95% CI 1.7–129.2, p = 0.02).ConclusionsImproved terminal insomnia is associated with improved SI following clozapine treatment. Findings warrant replication in a larger sample with standard instruments in the assessment of insomnia and suicide, but suggest beneficial effects on sleep as a mediator of the anti‐suicidal properties of clozapine. Future mechanistic studies are also needed.